Side seam lock for containers



April 2, 1957 c. L- NYLANDER SIDE SEAM LOCK FOR CONTAINERS Filed July 18, 1955 INVENTOR'. CARL L. NYLANDER hillll ATTORNB S United States Patent "ice SIDE SEAM LOCK FOR CONTAINERS Carl L. Nylander, Oakland, Calif. Application July 18, 1955, Serial No. 522,429

3 Claims. (Cl. 220-77) The invention relates generally to solder-bonded side seams for cylindrical sheet metal containers and more particularly to a positively interlocking type of side seam construction.

- Conventional side seam construction involves the use of a reversely bent and interengaged pair of hooks pressed or bumped together into tight frictional contact prior to soldering. While the conventional hook construction is capable of preventing separation of the edges when the container is subjected to forces tending to pull the edges apart, that is to say, in a direction tending to increase the diameter of the cylindrical container, the impositive frictional engagement resulting from the pressing or bumping step is often unable to prevent unhooking when the container is subjected to forces tending to reduce its diameter. If, in other words, the two engaging edges of the usual container are pushed toward each other, prior to soldering, the hooks slide over one another in an opening direction and, if continued far enough, result in complete disengagement of the hooks. Even a partial separation of the hooks produces an undesirably large solder channel and an off-size can while complete separation results in an unusable product.

It is therefore an object of the side seam lock of my invention to provide a positive interengagernent between the hooks capable of maintaining the diameter of an inprocess can to close tolerances.

It is another object of the invention to provide a side seam lock which can be inexpensively produced and which is easily adaptable to present-day can making operations.

It is yet another object of the invention to provide a side seam lock which permits the gases generated by the soldering operation easily to escape.

it is a further object of the invention to provide a side seam lock which furnishes an improved flow of molten solder and thus a stronger side seam bond.

It is a still further object of the invention to provide a side seam lock which is attractive in aspect and relatively smooth to the touch.

Another object of the invention is to provide a generally improved side seam lock for sheet metal containers.

Other objects, together with the foregoing, are attained in the embodiment described below and shown in the accompanying drawings, in which:

Figure l is a perspective of a cylindrical sheet metal body provided with the side seam lock of the invention.

Figure 2 is a partial view of one end of a prepared sheet metal blank showing the opposite facing side edges prior to folding of the edge hooks.

Figure 3 resembles Figure 2 but with the edge hooks in folded position.

Figure 4 is a view of the side seam lock subsequent to interengagement of the hooks and staking of the lock buttons, portions being broken away to show the underlying construction.

2,787,401 Patented Apr. 2,, 195 7 Figure 5 is a sectional view, the plane of section being indicated by the line 5-5 in Figure 2.

Figure 6 is a sectional view, to an enlarged scale of the interengaged edge hooks before the staking of the lock buttons.

Figure 7 is a sectional view take along the same plane as the showing in Figure 6 but with the lock buttons formed and the seam soldered.

Figure 8 is a sectional view similar to Figure 7 but with the semi-circular recess on the opposite edge hook and with the button and the crown struck downwardly rather than upwardly.

In the fabrication of a cylindrical container body 8 utilized in conjunction with the side seam lock 9 of my invention, a container body blank 11, usually rectangular in outline, is stamped from a piece of sheet metal and rolled into tubular form. The opposite facing side edges 12 and 13 are configured to diflering outlines, the configurations often being impressed on the blank at the time the blank is stamped out. While all of the corners of the blank are clipped, as at 14, in the conventional way, the edge 12 is caused to assume an outline at variance from the edge 13.

The edge 12 is notched out at both ends, as at 18, the notch 18 forming a flange 19, or flap, projecting from a base-line 21, or fold line, the fold line being an extension of the base 22 of the notch 18. The width of the flange 19 is determined by the dimension of the side 23 of the notch, the flange extending from the base line 22 to a margin 24.

A mating or matching flange 30, or flap, is provided on the side edge 13 by virtue of a slit 31, or cut, extending inwardly from a margin 32 to a fold line 33. Upon folding the flange 30 upwardly about the fold line 33, and to a reverse attitude, as shown most clearly in Figures 3 and 5, a folded edge margin 34 is provided, the margin 34 being in substantially facing relation with the folded edge margin 29 of the opposite side edge.

Piercing the edge 12, along the fold line 21 is a plu rality of circular apertures 26 having a radius approximately equal to one-half the width of the flange 19, each aperture forming, in outline, a neck portion 27 in the flange. When the flange 19 is folded downwardly about the fold line and into a reversed position, as appears most clearly in Figures 3 and 5, the apertures 26 provide a plurality of semi-circular recesses 28, or notches interrupting the folded edge margin 29.

The reversely disposed flange 30 and underlying body portion are, by appropriate mechanism well known in the art, offset in a downward direction, and the flange and body thereupon assume the configuration shown in Figure 6. The struck-down portion 36, or downset, is suitably contoured and dimensioned so that the upper, or outermost, surfaces of the side edges 12 and 13 are substantially co-planar and thus offer a smooth seam surface.

As can be seen most clearly in Figures 3, 5 and 6, the reversely disposed flanges 19 and 30 form, in conjunction with the corresponding edges 12 and 13, an outer hook 41 and an inner hook 42, respectively.

The hooks 41 and 42 are disposed in interengaging relation, with their adjacent surfaces in interfacing position, as shown in Figure 6. At this juncture, the downset portions 36 adjacent each of the semi-circular recesses 28 are struck outwardly, or upwardly as appears in Figure 7, causing the material to be deformed into the configuration shown in Figure 7. The downset portion 36, in other words, is caused to assume the form of a raised button 37, as shown in Figures 4 and 7.

Th'button 37, it will be observed, extends upwardly into the semi-circular recess 28, the crimping upwardly Additional resistance to separation is provided as a consequence of the outward or upward deformation of a semi-circular crowned portion 38 of the flange margin 32, the deformation of the crown 38 being caused by the upward thrust of the button 37. The crown 38 extends into the uppermost portion of the recess 28 and abuts the adjacent margin 43 of the recess, thus serving even more tightly and positively to lock the hooks together. V n

It is further to be noted that the upward thrust or hump of the crown portion 38 serves substantially to fill the gap created by the recess 23 in the otherwise smooth margin 29 of the side edge 12, thus enhancing the appearance of the side seam and making the surface smoother to the sense of touch.

Owing tothe clamping effect of the button 37 and thecrownedportion 38 on the neck 2'7 of the outer hook, and as a consequence of the crowns being in abutment with the recess margin 43, a container being processed and prior to soldering will maintain its diameter to a close tolerance even though subjected to considerable bulfeting.

The beneficial effect of the positive lock created by the button 37 and the crown 3% located in the registering recess is also felt when the soldering operation is under taken. As the solder 46 is applied to the seam surface, the metal flows between the hook interfaces creating a bond which serves to seal and strengthen the seam. The plurality of button locks permits the solder to flow into the interior of the seam more directly and the recesses promote the escape of gases arising as a consequence of the application of the molten solder to the seam. A uniform layer is therefore provided.

As the solder cools, the solder metal assumes substantially the shape appearing in Figure 7. it is to be noted that the button 37 and the crown 38 are bonded together, thus encircling the outer hook neck 27 and adding strength to the seam lock.

Figure 8 represents an alternative construction differing from that previously described only in that the recesses 2S are formed on the inner or lower hook 42 rather than on the outer or upper hook 41. This alternative construction is especially suitable for use with cemented seams in which the bonding agent is preferably located in the space inside the outer hook prior to interengagement of the hooks. As bumping or pressing together of the hooks then takes place, an appropriately configured protuberance on the bumping member depresses the metal on the outer hook body adjacent a neck portion 47 on the inner hook so as to form a downwardly directed button 48 and a corresponding downwardly or inwardly bent crown 49.

It can therefore be seen that the side seam lock of my invention not only provides a strong finished seam, but it also furnishes a rigid and positive interlock between the side edges of a sheet metal container during the inprocess phase of its manufacture, a critical period when close tolerances must be maintained.

What is claimed is:

1'. A side seam lock comprising a body blank roHedinfo cylindrical form having an} interlocking first hook and second hook, said first hook including a flange folded about a fold line to underlie an adjacent first body portion, said fold line being interrupted by a plurality of registering semi-circular recesses formed in said flange and said adjacent first body portion, said second hook including a flap folded about a' fold line' to overlie an adjacent second body portion, said second body portion being deformed adjacent each" of said recesses to form a button extending into each of said recesses, said fiap being deformed adjacent each of said recesses to provide a plurality of crowns overlying the corresponding one of said buttons in substantially face to face relation.

2. A side seam for a tubular sheet metal body having attached thereto on opposite edges a first reversely bent hook, and a second reversely bent hook, said hooks being adapted for overlapping and interen'gaging relation, each of said hooks extending from a fold line in a direction parallel to and spaced from the attached body portion,v

one of said hooks having formed therein along said fold line a plurality of recesses extending into the attached body portion and into said one of said hooks an amount substantially equal to one-half the distance be tween said fold line and said margin, said one of said hooks incniding a plurality of neck portions each defined by the hook material extending between each of said recesses in said hook and said margin thereof, the other of said hooks and the adjacent portion of the attached body being deformed adjacent said recesses in a direction toward said recesses whereby each of said neck portions is enclosed and the marginal portion of said other of said hooks substantially fills said recess in said body portion attached to saidone of said hooks.

3. A side seam lock for sheet metal containers including a body having a pair of facing edges, one of said edges comprising a flange recurved about a fold line, said fold line having formed therein a plurality of apertures where by said fold line is interrupted by a plurality of registeringrecesses in said flange and in the attached body portion as said flange is bent with respect to said body portion about said fold line, each of said recesses in said References Cited in the file of this patent UNITED STATES PATENTS 2,616,588 Heinle Nov. 4, 1952 FOREIGN PATENTS 505,671 Great Britain May 16, 1939 

